Article stringing machine having a strand control gripper



H. A. IMHOF 3,183,867

ARTICLE STRINGING MACHINE HAVING A STRAND CONTROL GRIPPER May 18, 1965Filed Aug. 14, 1963 United States P t n 0.

. 3,183,867 ARTICLE STRlNGING MACHINE HAVING A STRAND CONTROL GRIPPERHerman A. Imhof, Hamilton, Mass., assignor to United Shoe MachineryCorporation, Boston, Mass, 21 corporation of New Jersey Filed Aug. 14,1963, Ser. No. 302,158 Claims. (Cl. 112-104) This invention relatesgenerally to improvements in article stringing machines and moreparticularly to strand engaging and controlling devices especiallyuseful in such machines.

The operating requirements of stringing machines such as that disclosedin application Serial No. 117,219, filed June 15, 1961 in the names ofCharles P. Cardani et al., now Patent No. 3,142,896, create a variety ofstrand management conditions during an operating cycle of the machine.Such machines, generally speaking, carry the leading end of a strand bymeans of an eye-pointed needle through one or a pair of articles. Afterthe point of maximum penetration of the needle is reached the needle isretracted to form a bulge in the strand and a first pincer grips theleading end of the strand. Thereafter the needle is completely retractedand a quantity of strand is measured or stored to be used later informing a closed loop passing through an article or articles. Thenanintermediate point of the strand is gripped by a second pincer,

and the strand is severed between the second pincer and the strandsupply. The two ends of the length of strand are then manipulated by thepincers into overlapped bights which are secured together by means of aclinched eyelet.

Article stringing machines operate most reliably when the strand isfrictionally engaged between the needle eye and the strand supply at thebeginning and near the end of the operating cycle of the machine.Otherwise, as the needle is set in motion toward the work pieces at thebeginning of the cycle, there is a tendency for the needle to becomepartially or completely unthreaded if the strand is carried .by theneedle eye only. Also the measurement or storage of the quantity ofstrand later in the operating cycle of the machine is best accomplishedwhen motion of the strand is under light tension provided by frictionalengagement. On the other hand, while the needle is penetrating thearticles and is being partially withdrawn to form a bulge in the leadingend of the strand to be gripped by the first pincer, the material of thework pieces and other strand contacting devices provide frictionalresistance upon the leading end portion of the strand to insure thenecessary control for insuring formation of the bulge to be gripped bythe first pincer.

A general object of the present invention is accordingly to improvethereiiability of operation of article stringing machines.

A more particular object is to provide for the application andrelaxation of a frictional drag upon the strand in accordance with therequirements of ditferent parts of the cycle of article stringingmachines.

Another object is to achieve reliable entrainment of the leading end ofthe strand with the needle as the needle is first set'into motion at thebeginning of each operating cycle of an article stringing machine. V

j Still another object is the achievement of light tension upon thestrand by frictional control while the quantity of the strandlis beingnieasured in an article stringing 3,183,867 Patented May 1s, was

machine. It is a further object to provide the above frictional controlof the strand in article stringing machines while making the strand freeof frictional engagement during other portions of the machine cycle.

It is still another object to provide strand control devices which arerelatively insensitive to changes in size and type of strand and whichalso require a minimum of attention in order to operate effectively overextended periods of time.

In the achievement of the foregoing objects a feature of the inventionresides in a pivotallymounted cam actuated strand control member. Thepivot for the member which is in the form of a lever is so located thata small motion is necessary to change from strand engaging to strandreleasing condition and vice versa. The friction member is urged intoengagement with the strand by a coil spring and camming is provided by astationary tab in the path of the lever which has a motion coinciding inpart with that of the needle. Threading of the machine is facilitated bythe form of the thread engaging end of the member and by a tab forreleasing the member against the bias of the spring.

The foregoing objects and features will be more fully appreciated fromthe following description of an illustrative embodiment taken inconnection with the accompanying drawings in which,

FIG. 1 is airagmentary View in front elevation of an article stringingmachine including a strand controlling friction device according to thepresent invention;

PEG. 2 is a fragmentary view on an enlarged scale showing the operationof the strand controlling device of FIG. 1, at the beginning ofpenetration of a work piece by the needle of the machine;

FIG. 3 is a view in perspective of the strand control device included inFIGS. 1 and 2 with some of its parts shown in exploded relationship; and

FIG. 4 is a detail view in perspective of a strand control member whichis a part of the device of the previous views.

Referring particularly to FIG. 1, the present machine includes a curvedeye-pointed needle 10 mounted in a needle carrier 12 to be oscillatedfor penetrating a pair of articles shown at 14, 16 for carrying theleading end of a strand 18 through articles or work pieces 14, 16 heldin stringing position against a pedestal 20 by clamps indicated at 22,24, respectively. Also included in the machine are left and rightpincers indicated at 26 and 28 respectively for manipulating the strandafter the leading end has been carried through the work pieces. Theneedle 16 is supported against deflection while penetrating the workpieces by a main needle guide 30 and its central portion is additionallysupported by an auxiliary guide 32.

The main guide 30 is mounted concentrically with the carrier 12 andurged in a clockwise direction as the needle travels toward the pedestal29, by a torsion spring 34 interposed between the carrier 12 and themain guide '30.

The machine elements already described are more fully disclosed in theabove-identified application and in other copending applications andform no part of the present invention but serve merely as a basis forthe present improvement. i

V For controlling the flow of the strand 18 there is pro- .vided,according to the present invention, a three-armed friction leverincluding a strand engaging arm 36, a pivot arm 38 and a cam arm 40. Thearm 38 is pivoted at 42 on a lug 43 integrally formed on the needleguide 30 which surrounds a forward extension of the needle carrier 12 inturn journaled on a shaft 46. The pivot arm 38, as may be seen in FIG.4, is made up of two downwardly bent tabs formed integral with the leverarms 36, 40. Between two tabs of the arm 38 there is included a spacerbushing 48 surrounding a rivet 50 to add rigidity to the structure.

The strand control lever is urged in a counterclockwise or strandengaging direction by. a compression spring 52 fitted into a'socket inthe needle guide 30 and maintained in position against the arm 4% by apin 54. In order to limit the motion of the strand control lever the arm36 is pierced at 56 and a headed shoulder screw 58 passes looselythrough the opening in the arm and is threaded into the needle guide 30.The head of the screw is so spaced from the arm 36 as to permit thecontrol lever to move only sufliciently to release the strand 18.

It is important as the needle starts toward the pedestal 20 at thebeginning of an operating cycle of the machine that the strand 18 befirmly gripped to prevent the strand from remaining stationary as theneedle advances thus unthreading the needle. At the beginning of theneedle motion the force of the spring 52 therefore bears fully to gripthe strand 18 as seen in FIGS. 1 and 3.

The leading end portion of the strand lying on both sides of the needleeye is most easily controlled if the strand is free of frictional dragduring the period of time commencing as the needle eye penetrates thearticle 14 until it is withdrawn from the article. For this reason thereis provided in the present machine means for eliminating the frictionapplied to the strand by the arm 36, during this period. To this end aWasher 60 which retains the needle guide 30 and the needle carrier 12 onthe shaft 46 is formed with a rearwardly bent projection 62 positionedto be engaged by the underside of the arm 4% as the needle guide 30approaches the clockwise extreme of its travel as shown in FIG. 2. Theengagement of the arm tiwith the projection 62 causes a slight rockingmotion of the strand control arm in a clockwise direction about thepivot 42 thus completely freeing the strand.

The measurement or temporary storing of strand to make up the closedloop passing through the articles, is

accomplished after the needle and needle guide have returned to thepositions shown in full lines in FIG. 1.

In order to insure accuracy of strand measurement it is necessary thatthe strand assume a predetermined position under the influence of ameasuring member and this is accomplished while the strand is underlight tension. Tension on the strand 18 is provided during measurementand the strand is maintained in a predetermined path defined in part bya wear resistant carbide channel insert 64 mounted in the distal end ofthe needle guide 30.

The orientation of the projection 62 is maintained by a small dowel 66passing through an opening in the washer 60 and pressed into the shaft46 and the washer is.

retained on the shaft by a screw 68 entering a central threaded openingin the shaft. 7

As seen from the foregoing, the strand control device, according to thepresent invention, applies a full frictional grip to overcome theinertia of the strand as the needle it starts in motion toward thepedestal 20 thereby preventing unthreading of the needle. In addition,as the needle guide 30 approaches the clockwise extreme of its traveland the needle 16 begins the penetration of the first article retainedby the clamp 22 onthe right side of the pedestal, as seen in FIG. 1, thecontrol of the strand is released by the pivotal movement imparted tothe lever 36,

46) by the projection 62. Thereafter when the needle guide 30 isreturned to its starting position, shown in solid lines in FIG. '1, thestrand control armfidagain applies a friction to the strand 18. Becauseof the fact that, at this time, the strand being measured is movingoutwardly through the needle eye, and in so doing entrains the arm 36 inthe direction of strand flow against the compresd sion of the spring 52,the frictional engagement is somewhat reduced but is adequate formaintaining the necessary control and insuring accuracy of strandmeasurement.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent of the United States is:

1. An article stringing machine comprising a curved eye-pointed needle,a needle carrier upon which the needle is mounted and actuated about anaxis to carry the leading end of a strand in an arcuate path in theneedle plane through a work piece, a needle guide journaled coaxiallywith the needle carrier for movement with the needle carrier a part ofthe distance toward the work piece, strand guiding means in the needleplane and formed in the needle guide, a strand control lever pivoted onthe needle guide, resilient means urging the lever toward a strandengaging position at the strand guiding means and means for actuatingthe lever away from the strand engaging position during'a part of theoperating cycle of the machine.

2. An article stringing machine comprising a curved eye-pointed needle,a needle carrier upon which the needle is mounted and actuated to carrythe leading end of a strand in a work penetrating stroke through a workpiece, a needle guide journaled for movement with the needle carriertoward the work piece, a spring urging the needle guide to move with theneedle during a part of the work penetrating stroke of the needle andpermitting the guide to remain stationary during another part of theneedle stroke, strand guiding means formed in the needle guide, a strandcontrol lever pivoted'on the needle guide, resilient means urging thelever toward a frictional strandengaging position at the strand guidingmeans and means including a stationary abutment in the path of the leverfor camming the lever away from the strand-engaging position during apart of the operating cycle of the machine.

3. An article stringing machine comprising a curved eye-pointed needle,a needle carrier upon which the needle is mounted and oscillated aboutan axis to carry the leading end of a strand through a work piece and towithdraw, a needle guide journaled concentrically with the carrier andurged to move with the needle carrier toward the work piece, strandguiding means formed in the end of the needle guide outside the radiusof needle curvature, a strand control lever pivoted inside the radius ofneedle curvature on the needle guide, formed with a perforated strandengaging surface through the perforation of which the needle and strandpass, resilient means urgmg the strand engaging surface of the levertoward a strand-engaging position at the strand guiding means and meansfor camrning the lever away from the strand-engaging position during apart of the cycle of the machine.

4. An article stringing machine comprising a curved eye-pointed needle,a needle carrier upon which the needle is mounted and actuated to carrythe leading end of a strand about an axis and through a work piece, aneedle guide journaled for movement with the needle carrier toward thework piece, a three-armed strand control lever, one arm of which ispivoted on the needle guide close to the axis of needle motion, anotherarm of which termimates in a strand engaging surface and the third armof which provides a cam engaging surface and a manually engageablerelease tab, resilient means acting on the lever to urge the strandengaging surface toward a strand-engaging position outside the radius ofneedle curvature, and means including a stationary abutment in the pathof the third arm of the lever for camming the strand engaging surface ofthe lever away from the strand-engaging position during apart of theoperating cycle of the machine.

5. An article stringing machine comprising a curved eye-pointed needle,a needle carrier upon which the needle is mounted and actuated to carrythe leading end 5 of a strand through a work piece, a needle guidejournaled for movement with the needle carrier toward the work piece, astrand control lever pivoted on the needle guide, inside the radius ofneedle curvature, resilient means urging the lever toward astrand-engaging position 5 for supplying greater frictional resistanceto strand movement in one direction than in the other and meansincluding a stationary abutment in the path of the lever for camming thelever away from the strand-engaging position While the needle is in thework piece.

amass? References Cited by the Examiner UNITED STATES PATENTS 766,7158/04 Lyons 112-253 2,191,046 2/40 Tiesler 112255 2,503,809 4/50 Eastman112--104 2,885,985 5/59 Kells 112-253 2,911,928 11/59 Burke 1121043,115,856 12/63 Card 112253 3,142,896 8/64 Cardoni et a1. 112-104 XJORDAN FRANKLIN, Pr'imary Examiner.

1. AN ARTICLE STRINGING MACHINE COMPRISING A CURVED EYE-POINTED NEEDLE,A NEEDLE CARRIER UPON WHICH THE NEEDLE IS MOUNTED AND ACTUATED ABOUT ANAXIS TO CARRY THE LEADING END OF A STAND IN AN ARCUATE PATH IN THENEEDLE PLANE THROUGH A WORK PIECE, A NEEDLE GUIDE JOURNALED COAXIALLYWITH THE NEEDLE CARRIER FOR MOVEMENT WITH THE NEEDLE CARRIER A PART OFTHE DISTANCE TOWARD THE WORK PIECE, STRAND GUIDING MEANS IN THE NEEDLEPLANE AND FORMED IN THE NEEDLE GUIDE, A STRAND CONTROL LEVER PIVOTED ONTHE NEEDLE GUIDE, RESILIENT MEANS URGING THE LEVER TOWARD A STRANDENGAGING POSITION AT THE STRAND GUIDING MEANS AND MEANS FOR ACTUATINGTHE LEVER AWAY FROM THE STRAND ENGAGING POSITION DURING A PART OF THEOPERATING CYCLE OF THE MACHINE.